One of the most common forms of routine interference in labour is an artificial rupture of membranes (ARM) – sometimes referred to as ‘breaking’ or ‘releasing’ your waters.

Protecting your baby – the important job of amniotic fluid

Amniotic fluid is a clear, slightly straw coloured fluid which surrounds the baby in pregnancy.

During your pregnancy, your baby is protected in the amniotic sac, which is in your uterus, and is made of two membranes. These membranes seal around your baby and the amniotic fluid. Your baby floats in the amniotic fluid safely within the amniotic sac for the duration of your pregnancy.

The amniotic fluid is constantly circulating and the amount corresponds to your baby’s growth. At the beginning of your pregnancy, your amniotic fluid will only be a few millimetres. At its peak volume, around the 36 week mark, you may have around 800ml to 1000ml of amniotic fluid. This gradually decreases until your baby is born. Your baby uses the amniotic fluid to practice ‘breathing’ – swallowing fluid into the lungs and urinating it out. For this reason, the fluid levels are constantly moving.

The amniotic fluid protects your baby in the following ways:

– acts as a cushion for any sudden blows, shocks, bounces you may receive

What are the types of ways your membranes may rupture?

Rupture of membranes – “your water breaking” – is when the membrane seal around the amniotic sac opens, usually due to the pressure of contractions or birth, and releases the fluid around your baby. You may notice a ‘gush’ of fluid or just a little trickle. This depends on the position of your baby, where the seal opens, and how much amniotic fluid you have. It is normal for your membranes to release spontaneously when you are term. It can happen before labour begins (around 15% of women) or for most women, in labour. Often, women’s membranes do not release until late labour or when they are pushing for the second stage. Other women’s membranes never release – they remain intact for the birth of their baby. This is called being born in the Caul. All are considered normal.

Your waters can also be ruptured manually by a health care provider. This may be suggested to you to artificially bring on your labour (induction), to try to speed your labour up, if your baby is showing signs of distress, or as routine practice under Active Management of Labour (AML).

These are the types of rupture of membranes:

SROM – stands for spontaneous rupture of membranes and is when your membranes release on their own (spontaneous) at term. Term is anywhere between 37 and 42 complete weeks.

PROM – stands for premature rupture of membranes and is when your membranes release on their own (spontaneous) before labour begins.

PPROM – stands for preterm, premature rupture of membranes and is when your membranes release on their own (spontaneous) before 37 weeks gestation.

ARM or AROM – stands for artificial rupture of membranes and is when your membranes are ruptured by your health care provider to induce or accelerate your labour.

Artificial Rupture of Membranes – ARM

Artificial Rupture of Membranes (ARM) may be discussed with you if your health care providers recommend your labour should be induced, to try to speed up your labour, or, if your baby is showing signs of distress. ARM may also be performed if your hospital follows Active Management of Labour as routine policy. Routine means that a practice is done as the norm for the majority of women, rather than on individual assessment or medical need.

Active Management of Labour (AML) is an approach to labour which was created in National Maternity Hospital, Holles Street, in Dublin and is now practiced in many obstetric led units. The principal of AML is to manage the time a woman is in labour to prevent ‘prolonged’ labour. The definition of ‘prolonged labour’ has changed over time. In 1963, prolonged labour was defined as 36 hours. This was changed to 24 hours in 1968 and was finally reduced to 12 hours in 1972. The main principals of AML are that you will have your waters broken, be given frequent vaginal exams to track your progress, and that your labour is considered to be progressing if you dilate 1cm per hour. Continuous electronic foetal monitoring is also used. Women who are not dilating 1cm per hour, have labour accelerated with a drug called syntocinon.

To perform an ARM, your health care provider will gently insert an amniohook into your vagina. An amniohook is a long thin plastic tool with a tiny hook on the end which pierces a tiny hole into the membranes to release the amniotic fluid. Most women report that having an ARM is not painful.

The intent of ARM is to:

* stimulate contractions to start labour (induction)
* strengthen contractions to prevent prolonged labour
* regulate contractions in a labour which has stalled or not progressed

The idea of shortening your labour may sound positive, however, as with all interventions, there are often trade-offs you need to consider before making a decision. Once an ARM is performed, your labour is closely monitored and you will be on time limits. You may also be advised to have continuous electronic foetal monitoring. Many women report labour as being more difficult following artificial rupture of membranes, requiring pain relief.

What Women Say:

“My waters were broken at 3cm. I was coping fairly well before but found once they were broken things got very intense and I asked for the epidural shortly after.”

And

“My first labour was 36 hours and only really got going once they broke my water. On my second, I asked to have my waters broken earlier in hoping to prevent the same thing happening”

And

“I never realised that once your waters were broken you are on the clock. In hindsight I should have gone home to wait instead of agreeing to have them broken”

And

“My waters were artificially released on my first two babies around 7cm and babies were born quickly thereafter. I honestly thought that I was just one of those people who need their waters broken to progress. On my third I had a homebirth and I laboured with waters intact until I was 10cm. The waters gently released as I started to get the need to bear down. Purely anecdotal but I found transition with my waters intact much more bearable”

And

” I was induced at 39 weeks by having an ARM on all 4 of my children – fantastic experiences each and every one of them!”

And

“On my first I was told I could not have gas and air until I went to the delivery suite…and I couldn’t go to delivery unless I let the break my waters, which I felt very strongly about”

Consent

As with all tests, procedures, and treatments, you will be required to consent for an ARM. Your care team should go through all the benefits (the advantages of ARM), the risks (the disadvantages of ARM), implications (associated risks of ARM) and possible future consequences of ARM, in order for you to make an informed decision. Labour is not necessarily the best time to hear this information for the first time, so it is recommended you discuss ARM, and other care options, with your care team at your ante-natal appointments. A birth plan can be an excellent way to initiate this discussion. You can read more about birth plans and preferences here AND here.

Your consent for ARM will be obtained verbally. If at any time you need anything explained to you, please ask. It is important that you understand what you are consenting to.

You should not be put under any pressure to commit to having your waters artificially broken in order to receive pain medication, gain access to the delivery suites, or to avoid routine interventions.

What the Evidence Says

Evidence does not support artificial rupture of membranes for women in normally progressing spontaneous labours or where a woman’s labour has become prolonged. The evidence shows that ARM does not shorten the first stage of labour.

The following are the advantages and disadvantage of artificial rupture of membranes:

Advantages:

* if your baby is showing signs of distress and requires internal monitoring – foetal scalp monitoring
* if your baby is showing signs of distress an ARM will show if there is meconium present (Note: meconium can be a sign of foetal distress but in many cases occurs in a normal healthy labour with no adverse affects)
* some research has shown it may shorten the second stage of labour in first time mothers